In the shell, you should be greeted by a query prompt "?-". At this prompt, you can issue queries against the program. Try entering the following query:

append(X,Y,[1,2,3,4]).

The shell should respond with this:

append([],[1,2,3,4],[1,2,3,4]) ;

It should then appear to hang. It's waiting for you to type a character. If you type a semi-colon, it will attempt to resatisfy the query. If you keep doing that until there are no more valid results left, you'll see this:

The "No" is just Prolog's way of telling you there are no more results which satisfy your query. If you stop trying to satisfy results before all solutions have been found, you might see something like this:

If you are hoping to use this to play the bundled "Spider" game, I recommend the following:

aiprolog location/of/spider.pro
?- % no more

That disables the pause where the shell waits for you to hit a ';' to get more results or hit enter to continue. It gets very annoying while playing the game, though it's useful when you really want to program.